Planned Shutdown of Lower Sundays River Canal for Rehabilitation

The Department of Water and Sanitation (DWS), Lower Sundays River Water User Association, and NMBMM will oversee the rehabilitation.

The Nelson Mandela Bay Metropolitan Municipality (NMBMM) and other stakeholders have announced a three-month shutdown of parts of the Lower Sundays River Canal for urgent rehabilitation work. The shutdown, scheduled from June 10 to August 15, 2024, aims to address critical damage to the canal, ensuring the reliable and sustainable supply of water.

Background and Urgency

The Lower Sundays River Canal, part of the Lower Sunday's Government Water Scheme (LSGWS), is essential for supplying bulk water to agricultural and domestic users in the region. It forms part of the larger Orange-Fish-Sundays Inter Basin Transfer Scheme, transferring 740 million kilolitres of water annually from the Gariep Dam to the Eastern Cape through an 80 km tunnel.

The need for repair stems from a May 2017 incident where a section of the canal embankment slipped, necessitating a temporary fix using a plastic membrane. A subsequent embankment failure occurred 200 meters downstream, highlighting the urgency for comprehensive rehabilitation.

Rehabilitation Details

The Department of Water and Sanitation (DWS), Lower Sundays River Water User Association, and NMBMM will oversee the rehabilitation. Key work includes:

Demolishing existing canal sections at upstream and downstream tie-ins.

Surface preparations and placement of a High-Density Polyethylene (HDPE) liner over the tie-in sections.

During construction, the canal will not be completely shut down. Intervals will allow water to flow through to supply end users once certain segments are repaired.

Impact on Water Supply and Mitigation Measures

The major domestic users affected by the shutdown will be the towns of Addo, Paterson, and the Nelson Mandela Bay Metro. However, measures have been put in place to minimize interruptions:

Kirkwood: Located upstream of the shutdown point, will continue to receive water from the main canal.

Addo and Paterson: Supplied by Caesar's Balancing Dam, which will be filled prior to the shutdown and recharged during intervals when the canal is opened.

Nelson Mandela Bay Metro (NMBM): Typically receiving 70% of its water from the Nooitgedaght Water Treatment Works (WTW), will be supplied from the Scheepersvlakte Balancing Dam during the shutdown. Reduced supply will be offset by increased water from the western systems through Loerie and Churchill Dams, and Loerie and Elandsjacht Water Treatment Works.

Stakeholder Consultation

The DWS has conducted extensive consultations with stakeholders to plan for this period and inform customers. Regular meetings continue to address any potential challenges and ensure a coordinated response during the shutdown.

This planned maintenance is critical to prevent the collapse of the water scheme and ensure the long-term sustainability of water supply to the region.